<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>获取指定年份的2月份的天数</title>
    <script>
        /*var a,b;
        (function (){
            alert(a);
            alert(b);
            var a = b = 3;
            alert(a);
            alert(b);
        })();
        alert(a);
        alert(b);*/

        var foo = function (x,y){
            return x - y;
        };
        function foo(x,y){
            return x+y;
        }
        var num = foo(1,2);
        console.log(num);
    </script>
</head>
<body>

</body>
</html>